Study and NOQAS star rating | Type | Data | Follow-up | Age, years | Sex | Number with symptom | Symptom | Comments |
---|---|---|---|---|---|---|---|---|
Hamilton et al, 200924 (8 stars) | Case-control | Routinely recorded computer codes | NA | ≥30 | M+F | 853 cases, 460 controls | Rectal bleeding computer codes | PPV stratified by age and sex but numbers of cases and controls by age and sex not given |
Hamilton et al, 200523 (9 stars) | Case-control | Routinely recorded data including free text | NA | ≥40 | M+F | 148 cases, 73 controls | Rectal bleeding | PPV 2.4% (95% CI = 1.9 to 3.2) |
Thompson et al, 199925 (3 stars) | Prospective cohort | Self-reported questionnaire | 4–5 years | >16 | M+F | 197 | Rectal bleeding and consulted GP | No cases of rectal cancer; two cases of caecal cancer felt not to cause bleeding but not stated if in consultation cohort |
Nørrelund and Nørrelund,199619 (3 stars) | Prospective cohort | Specifically registered | 22–57 months | ≥40 | M+F | 45 | Current bleeding episode similar to previous | PPV 4.4% (95% CI = 1.2 to 14.8) |
F = female. M = male. NA = not applicable. NOQAS = Newcastle-Ottawa Quality Assessment Scales. PPV = positive predictive value.